//! Render a `MizanError` as an axum `Response`: the JSON envelope
//! `{"error": {"code": ..., "message": ..., "details": ...}}` under a
//! `Cache-Control: no-store` header.

use axum::http::{header, HeaderValue, StatusCode};
use axum::response::{IntoResponse, Response};
use axum::Json;
use mizan_core::MizanError;

pub struct ApiError(pub MizanError);

impl From<MizanError> for ApiError {
    fn from(e: MizanError) -> Self {
        Self(e)
    }
}

/// Each variant's status spelled as an axum constant. Naming the constant
/// rather than round-tripping a `u16` leaves no numeric value axum could
/// reject, so the mapping is total.
fn status_of(err: &MizanError) -> StatusCode {
    match err {
        MizanError::NotFound(_) => StatusCode::NOT_FOUND,
        MizanError::BadRequest(_) => StatusCode::BAD_REQUEST,
        MizanError::ValidationFailed { .. } => StatusCode::UNPROCESSABLE_ENTITY,
        MizanError::Unauthorized(_) => StatusCode::UNAUTHORIZED,
        MizanError::Forbidden(_) => StatusCode::FORBIDDEN,
        MizanError::NotImplementedYet(_) => StatusCode::NOT_IMPLEMENTED,
        MizanError::InternalError(_) => StatusCode::INTERNAL_SERVER_ERROR,
    }
}

impl IntoResponse for ApiError {
    fn into_response(self) -> Response {
        let mut resp = (status_of(&self.0), Json(self.0.to_json())).into_response();
        resp.headers_mut()
            .insert(header::CACHE_CONTROL, HeaderValue::from_static("no-store"));
        resp
    }
}